Question

我有以下查询，列出了与其相关的类别和父类别。

t.term_id is the category ID
tx.parent is the ID of category from which they depend from. 
Main Categories have parent id= 0

这是问题，因为查询不显示主要类别而只显示子类别。基本上它只显示父＆gt; 0但我需要parent =＆gt; 0的记录。我已经把它放在了哪里，但是它没有用。

SELECT t.term_id, t.name, tx.parent, tm.name
from mg_terms t

join mg_term_taxonomy tx
on tx.term_id = t.term_id

join mg_terms tm
on tm.term_id = tx.parent

where tx.taxonomy='product_cat'  
ORDER BY `tx`.`parent`  DESC

获取主要类别（parent = 0）的任何帮助？

Answer 1

你可以使用UNION select并加入两个结果：

SELECT t.term_id, t.name, tx.parent, tm.name
FROM mg_terms t
JOIN mg_term_taxonomy tx ON tx.term_id = t.term_id
JOIN mg_terms tm ON tm.term_id = tx.parent
WHERE tx.taxonomy='product_cat'  
UNION 
SELECT t2.term_id, t2.name, tx2.parent, null
FROM mg_terms t2
JOIN mg_term_taxonomy tx2 ON tx2.term_id = t2.term_id
WHERE tx2.taxonomy='product_cat' AND t2.parent = 0
ORDER BY parent

或SELECT全部来自mg_terms t和LEFT JOIN mg_terms tm，同样由sagi建议。

SELECT t.term_id, t.name, tx.parent, tm.name
FROM mg_terms t
JOIN mg_term_taxonomy tx ON tx.term_id = t.term_id
LEFT JOIN mg_terms tm ON tm.term_id = tx.parent
WHERE tx.taxonomy='product_cat'  
ORDER BY `tx`.`parent`

MYSQL获取主要类别

1 个答案: